Cesarean sections: What are the pros and cons of regional and general anesthetics?
Regional and general anesthetics are equally safe for babies born by Cesarean section. But they have different advantages and disadvantages for the mothers.
A Cesarean section is needed if a baby can’t be born normally, or only with great difficulty. This might be the case, for instance, if the baby is lying sideways (transverse position) or if the placenta is blocking the opening of the womb (the cervix). According to the World Health Organization (WHO), Cesarean sections are medically necessary in about 10 to 15 percent of all births in Western countries. The actual percentage of Cesarean deliveries is generally higher, though. In Germany, for instance, about 30 percent of children are delivered by Cesarean section.
If everything goes smoothly, the operation takes about an hour in total. The baby can usually be taken out of the womb (uterus) within about 10 to 15 minutes, or even a lot faster in emergencies. The womb and the various layers of the abdomen are then carefully sewn up again.
Choice between general anesthetic and regional anesthetic
The mother is given an anesthetic throughout the whole operation. Women who have a Cesarean section usually have a choice of two or three options: A general anesthetic, where they are completely unconscious, and two types of regional anesthetic known as “epidural” and “spinal” anesthesia. Regional anesthetics numb the body from the waist down. The woman is awake for the birth and can see her child immediately afterwards.
In an epidural, the anesthetic is injected into the “epidural space” surrounding the spinal cord in the thoracic or lumbar regions of the spine. This only numbs the nerves that lead to the region of the spinal cord where the anesthetic was injected. Epidurals start relieving pain after 10 to 20 minutes.
In spinal anesthesia, also known as a spinal block, the medication is injected closer to the spinal cord: into the cerebrospinal fluid in the “subarachnoid space.” This causes the entire lower half of the body to feel numb. Spinal blocks work faster than epidurals, and a smaller amount of anesthetic medication is needed.
General anesthetics can be done faster, so they are used if the operation is an emergency, or if the woman can’t have a regional anesthetic. If there is more time, or if it’s a planned (“elective”) Cesarean section, then the woman might have a choice of anesthetic. Her decision will usually depend on whether or not she would like to be awake for the birth.
General anesthetics and regional anesthetics are associated with different risks. In general anesthesia, there is a risk of the woman vomiting while unconscious and the vomit getting into her lungs (called aspiration of stomach contents). Although this is very rare, it can be life-threatening.
Women who have an epidural or a spinal block occasionally experience a sudden major drop in blood pressure. They might also have a type of headache that can be caused by the injection into the epidural or subarachnoid space (“post-dural puncture headache”). In the past, Cesarean sections were nearly always done under general anesthetic, but nowadays more women and their doctors decide to do an epidural instead.
To compare the effectiveness and safety of the different options, researchers from the Cochrane Collaboration – an international network of researchers – looked for studies on the different types of anesthetics used in Cesarean sections. They found 29 studies involving about 1,800 women in total. Most of the women in the studies had pre-planned Cesarean sections.
There weren’t enough women in the different studies to be able to say whether general anesthetics are more likely to lead to serious complications like aspiration of stomach contents. This complication was generally rare.
But the studies were big enough to find out what side effects are likely to be most common in babies. These include things like breathing problems. There were no major differences between the various types of anesthetics here.
Women who had the operation under general anesthetic lost about 100 milliliters of blood more on average. But this didn’t cause any major health problems. For instance, the number of women who needed blood transfusions after the operation wasn’t influenced by the type of anesthetic used. But women who had a regional anesthetic were more likely to experience nausea and vomiting afterwards.
Sometimes women who have a Cesarean section under regional anesthetic might feel mild discomfort or even pain during the operation because, unlike with general anesthesia, they are still awake. If this happens, the anesthesiologist can give them more painkillers or sedatives.
Some studies looked into whether women had pain after their Cesarean section. They found that women who had a general anesthetic needed to get pain relief sooner after the operation than women who had a regional anesthetic. This is because the medication used in general anesthesia wears off more quickly than the medication used in epidurals.
Afolabi BB, Lesi FE. Regional versus general anaesthesia for caesarean section. Cochrane Database Syst Rev 2012; (10): CD004350.
World Health Organization (WHO). Identifying barriers and facilitators towards implementing guidelines to reduce caesarean section rates in Quebec. Bulletin of the World Health Organization 2007; 85: 733-820.
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